1. 添加ScriptManager1 到Asp.Net页面中

2. Page_Load 代码：

        protected void Page_Load(object sender, EventArgs e)
        {
            var scriptRef = AjaxControlToolkit.ScriptObjectBuilder.GetScriptReferences(
                                             typeof(AjaxControlToolkit.HTMLEditor.Editor)).ToList();
            scriptRef.ForEach(sr => ScriptManager1.Scripts.Add(sr));
        }